Throughout this application, various publications are referenced to as footnotes or within parentheses. Disclosures of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this invention pertains. Full bibliographic citations for these references may be found within or at the end of this application, preceding the claims.
The mammalian olfactory system consists of approximately one thousand unique receptors (1). The distinctive characteristic of this system is cross-reactivity, i.e. one receptor may react with many odorants, and one odorant may react with many receptors. Thus, an odorant is not characterized by a single and specific interaction, but rather through a pattern of massively parallel responses yielding fingerprints characteristic for that specific odorant. Attempts to mimic the mammalian olfactory system have led to the development of “electronic noses”, or arrays of cross-reactive sensors (2). In cross-reactive arrays, instead of standard dose-response curves, analytical samples are matched through their characteristic fingerprints to available standards. However, the frameworks suitable for the incremental variations of structure necessary to achieve differential cross-reactivity are currently limited. It would be useful to provide biomolecular receptors based on nucleic-acid three-way junctions that can be adapted to yield cross-reacting arrays for fingerprinting of solutions containing hydrophobic molecules.